Document History Data Loss

Today June 20th, I was writing a document from hand, and I used some cards to insert into the document.

Unlike usual, something went wrong, and the original hand written manuscript version was not saved in the document history; the document history starts from one of the latest card inserts and edits, so I am unable to revert to the original hand written manuscript or refer back to what I had written before.

This is the first time I am encountering this, and I have no idea what caused it. I have attempted reloading the page to see if it was just a hiccup in the UI/UX, but nothing changed.